A final stable release of the Plumi 4.5 buildout package is available, based on Plone 4.2.
You can download the file at http://pypi.python.org/pypi/plumi.app/
Detailed installation instructions can be found in the installation section of the Plumi manual on the Floss Manuals site. HOWEVER, THESE ARE NOT ALWAYS UP TO DATE. Please consult the install.txt for latest instructions!
A buildout puts together Zope, Plone, the third-party products and all customisations into one package. This makes it very easy for you to get everything up and running very quickly.
Installing & Developing Plone
Plumi is based on Plone. The Plone developers manual covers installation, development and troubleshooting of Plone sites.